Electrically insulating wire and other electrical conductors.



I UNITED, sTArEs PATENT OFFICE.

ALLEN D. 'WI-IIIPLE, OF CHICAGO, ILLINOIS.

ELECTRICALLY lNs uLATlNG WlRE AND OTHER ELECTRICAL CONDUCTORS Patented May 28, 1907.

Application filed Ncvember 11,1905. Serial Ilia. 286,973.

' To all whom it mag concern:

Be it known that I, ALLEN'D. WHIPPLE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illi nois, have inventeda certain new and useful Process for Electrically Insulating Wire and other Electrical Conductors, of which the following is a description.

My improved process relates to the method of insulating wire or'other metallic surfaces by coating the same with a li uid or semiliquid of such nature that. w en dried or baked thereon it willleave adherin thereto a layer of sufficient thickness and 0 suitable character to electrically insulate the same. If a single coat or layer is a plied, however, it must'necessarily be limite as to thickness. To overcome this the same material is sometimes employed for two or more coats to in crease the thickness and thus improve insulation in that respect, or to insure a perfect layer of'the material atall points on the surface of the conductor. The material usually em loyed is more or lessfsoluble, however) an the succeeding coats of the same liquid" material is to a considerable extent a solvent of the first coat applied, so that in any process where wire, for example, is passed through. a bath of the liquid, the preceding layer or layers are impaired to a considerable extent, increasing t The solvent effect of the superimposed layers or coats is also liable to be more active or marked at some points than at others, resulting in an insulatin coat of irregular and varying thickness. T e value of insulation, however, depends largely upon securing an insulating covering A of uniform thickness since a'thin spot must be the weakest from an insulation standpoint, and slight use .or abrasion at that polnt may render the entire insulation useless. I

My invention has for its object the elimination of the above objectionable features in a simple and eflicient manner, and to this end it consists in the novel process of accor iplishing such insulation by laying on a plurality of insulating coats, each of such a nature as to be anon-solvent of the next'preceding coat.

It also consists in such other improvements as are herein mentioned, and are more particularly pointed out in the claims.

In practicmg my process I prefer to employsuch insulating material that the usual baking step may be dispensedwith, thus,

e expense and labor,

cheapening the operation to a considerable extent and enabling the use of materials that would otherwise not be available. This may be accomplished by using a material that will set within a reasonably short time in the atmosphere and conducting the process in a manner that will permit such exposure.

of the conductor and readily dry on exposure to the atmosphere. Thus I have employed for this purpose collodion dissolved in ether to secure the proper viscosity and consisten'cy, for the first coat, and, after this has suitably set, applying a second coat of shellac dissolved in wood alcohol to secure the proper consistency for the purpose.

In practice I prefer to use an anilin or other suitable dye of any preferred shade in In practice I have accomplished'sati-sfactory results by using a viscous volatile liquid that will suitably adhere to the surfacethe first coat as the difierence in color clearly indicates when the surface of the conductor is evenly and suitably covered. However, any or all the different layers may be colored if desired. Additional layers may be added as desired to secure the re uired thickness of insulation, the two materia s being alternated that one coat may not be dissolved or affected by the next succeeding layer. By using the materials mentioned, or their equivalents for the purpose, wire may be passed through a bath of the insulating material and thence to a suitable reel or reels which is arranged at a sufiicient distance from the bath and is rotated at a speed to permit the material to substantially set before reaching the support. With the materials mentioned also the insulation is both substantially waterproof and of suflicient flexibility for the general use of conducting wires. The first coat employed need not necessarily adhere directly to the conductor wire, but should in all cases be sufliciently tenacious to serve as a covering for the wire and as a body for the superimposed layer or layers. If desired also the conductor may be covered with silk, cotton or the like previous to laying on the first 'coat, the steps of the process being the same 5 grains of beeswax and sufficient kerosene oil to thin the mixture when cold to the desired viscosity, and, after baking the same to set it, laying on a second coat of copal or dammar varnish and drying the same as desired by passing the conductor through a drying oven. The thickness of the insulation may be increased as desireddepending upon the size and use of the conductor.

The important feature of my invention consists in employing a plurality of coats of viscous insulating material either alone or in combination With other covering, in which each layer is allowed to set before another is applied and in which each coat or layer is a non-solvent of the'neXt preceding coat or layer.

By the term viscous fluid in the claims I Wish to be'understood as meaning a material or mixture of materials of sufficient fluidity to spread and set evenly upon the surface of the.conductor, and of sufficient adhesive qualities to suitably adhere to the surfaceof the conductor or to a preceding layer of insulating material during the setting stage. By the term set in the claims I also, I Wish to be understood as meaning sufficiently dried Whether by baking, ex

the same With a plurality-of layers of highly volatile viscous fluid insulating material in which each layer is chemically different from and a non-solvent of the preceding layer, each layer being allowed to set before am other layer is applied.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

' ALLEN D. VVHIPPLE.

Witnesses:

ROY W. HILL, CHARLES I. Conn. 

